A tubular bagging machine of the above-mentioned type is known for example from German OS 22 24 407. This tubular bagging machine provides in combination both a filling and also a welding of the tubular bag, the cross-welding jaws producing thereby simultaneously the upper cross-welding seam of an already filled tubular bag and the lower cross-welding seam of a still empty tubular bag. The upper tubular bag, the lower cross-welding seam of which is produced at this time, is subsequently filled through a fill pipe with material to be packaged. The cam track has the purpose in this tubular bagging machine to adjust the cross-welding jaws cyclically to the movement and filling of the tubular bag, to separate them from the tubular bag and to subsequently press them against the tubular bag. The closed design of the cam track permits a rotating movement of the cross-welding jaws, so that it is possible in particular to move the foil tube on during the welding operation together with the cross-welding jaws.
With conventional tubular bagging machines, it is difficult to enclose purposefully a specific amount of air in the bag together with the material to be packaged. Since the cross-welding jaws, when resting against the foil tube, prevent air or gases from exiting the foil tube due to the bearing pressure needed for welding, the amount of gas enclosed happens rather accidentally depending on the respective design of the tubular bag. Since under certain manufacturing conditions the weight of an already finished tubular bag burdens a foil tube to be welded and pulls same downwardly, same is, depending on the weight of the material to be filled, pulled and stretched downwardly with differing strength, thus also reducing the amount of the enclosed gas compared with a foil tube, which, the moment in which the cross-welding jaws approach the tube, can expand farther due to a smaller pull.
The basic purpose of the invention is to provide a tubular bagging machine of the above-mentioned type, which with a simple design and reliable operation enables a purposeful influence on the amount of gas to be enclosed in a bag.